When Mrs Thatcher became leader of the Conservative Party in 1975, Foreign Office concerns over her position on Israel were summed up by Michael Tait of the British embassy in Amman: “It is presumably in the national interest to do what we can to counter Arab fears and suspicions that the leader of HM opposition is already a prisoner of the Zionists.” In 1979, Thatcher resisted the initiative of her Foreign Secretary, Lord Carrington, to support Palestinian self-determination and closer ties to the Palestinian Liberation Organisation. During a visit to Kuwait in 1981, Thatcher told her hosts that she would not authorise ministerial meetings with the PLO because of its involvement in terrorism. She added that the PLO’s “real objective is to drive Israel into the sea and wipe it off the face of the globe”.

And yet she endorsed the landmark EEC Venice Declaration of 1980 which called for Palestinian self-determination and a role for the PLO in peace negotiations. This resulted in a full-blown crisis in relations between Britain and Israel. The crisis worsened when Britain condemned Israel’s invasion of Lebanon in 1982. There were further paradoxes. Thatcher opposed Foreign Office ambitions to upgrade contacts with the PLO, but she still invited two officials from the organisation to London as part of a Jordanian-Palestinian delegation in 1985, in a bid to break the deadlock in the Israeli-Palestinian conflict. She also approved higher-level contacts with the PLO in 1989 when it finally appeared to renounce terrorism and recognise Israel.

The same pattern is evident in Theresa May’s policy towards Israel. In December 2016, in an impassioned address to the Conservative Friends of Israel, she spoke of her pride in the Balfour Declaration, calling Israel “a remarkable country . . . a thriving democracy . . . and an example to the rest of the world.” She criticised the former US Secretary of State, John Kerry, over UN Security Council resolution 2334 which condemned Israel for its settlement expansion policy in the West Bank. This is particularly odd since Britain voted for resolution 2334 and also played a key role in crafting it and ensuring its passage through the Security Council.

Mrs May hosted Israel’s prime minister Benjamin Netanyahu in November 2017 to mark the centenary of the Balfour Declaration and expressed her pride in the relationship that Britain has built with Israel. However, her government was one of 22 EU countries that voted for the UN General Assembly resolution which rejected Donald Trump’s unilateral recognition of Jerusalem as Israel’s capital.

So what does all this mean? Tempting as it may be to view the Foreign Office and the EU as major constraints on Number Ten’s support for Israel, it is important to remember that no British prime minister has supported Israel’s settlement building policy in the West Bank. In her policy towards Israel, Thatcher was constrained less by the Foreign Office and more by the importance she placed on strong relationships with Britain’s moderate Arab allies. In my book, Margaret Thatcher and the Middle East (Cambridge, £22.99), I argue that the British leader’s concern over the threat posed by the Soviet Union was the decisive influence on her Middle East policy. Thatcher’s early support for Israel was related to her admiration for it as an oasis of democracy in the Middle East but also directly linked to her belief that it would be the only country in the region to resist the danger of Communist expansionism. Over time, however, she feared that the failure to resolve the Arab-Israeli conflict would be exploited by the Soviets, who had championed the Palestinian cause as a means to strengthen their regional influence.